Measuring instrument.



B. N. DAVIS.

MEASURING INSTRUMENT. APPLICATION FILED MAR.27. |914.

IBEMISS N. DAVIS, OF NEW OLEANS, LOUISIANA.

'MEASURING INSTRUMENT.

Application led March 27, 1914. Serial No. 827,568.

To all whom z'tmay concern.'

Be it known that I, BEMrss N. DAVIS, a citizen of the United States,residing at the city of New Orleans, in the parish of Orleans and Stateof Louisiana, have invented certain new and useful Improvements inMeasuring Instruments, of which the following is a full, clear, andexact description.

This invention relates to electrical measuring instruments and has forone of its purposes the provision of an instrument where by the quantityor amount of material carried by an endless conveyer for any givenperiod of time is automatically calculated and may be read from a directreading scale. To carry out this purpose, my invention contemplatesplacing an electrical integrating meter in circuit with adynamo-electric machine -connected to a rotating part of the conveyer sothat it will deliver current to the meter in direct proportion to thespeed at which the conveyer isl driven, and in providing means forvarying the current which is supplied to the meter in proportion to theweight of the quantity of the material which passes over a given pointat a given instant, which instantaneous values are iny any of thewell-known formsof scale contegrated in the meter to give a reading1ndicating the total weight of the material carried by the conveyer.

The instrument is therefore preferably calibrated to read in bushels,tons or other units, depending upon the material carried by theconveyer.

The measuring instrument is not, however, limited to use as anautomatically weighing device, but is capable of a broad application andadaptation varied uses as will be apparent to in mechanical arts, and asan example of one lof these adaptations, a modification is shown inwhich the instrument is operatively associated with a rotating shaft,where it may be used to give either a direct reading of the horse-powerrequired to drive the shaft or the total horsepower-hours consumed indriving the shaft for any period'of time.

Numerous other adaptations will be ap parent to those skilled in the artand it is my intention that the invention be limited only -by the scopeof the claims appended hereto.

In the drawings:

Figure 1 is a diagrammatic view ofy an instrument constructed inaccordance with and embodying the features 'of my invention,

to numerous an Specification of Letters Patent.

tion of the upper part d tacts 11. one skilled Patented Mar. 25, i919.

showing it adapted to be used as a belt conveyer weighing device.

Fig. 2 is a diagrammatic view of the same instrument operativelyassociated with a rotating shaft.

Referring first to Fig. 1, the numeral 1 designates broadly an endlessbelt conveyer of the ordinary construction which is adapted to carrymaterials such as wheat, coal and the like.- This belt conveyer isdriven by la pulley passes at one end, while at asses over an idlepulley 3. The upper half of the belt which carries the material issupported by rollers or carriers 4, which are vin turn'supported in theframe of the carrier (not shown). Arranged beneath a porof the belt 1 isa -scale platform 5, on which is mounted a plurality of carriers orsupporting rollers 4; similar to the-carriers 4: through which rollersthe weight of the material carried by the belt conveyer is transmittedto 'the scale platform. A. pivotedpointenor indicator 6 is moved over ascale 6 in direct proportion t-o the weight of the mass of materialsustained by the scale platform 5, by means of in the drawings, thepointer shown connected to a sysa spiral spring 8 simi- Preferablymounted on a shaft 9 whichcarries a pointer 6, is an arm 10 of arheostat having resistance coils v11, vthe end of which coils areconnected to a series of con- The arm 10 carries at its outer end ablade or brush which is adapted to contact with the contacts 11 to cutthe resistance coils in or out of circuit, the blade being of sufficientwidth thatfin the angular movement of the arm the blade will Vbridge thecontacts 11?, or, in other words, the arm 10 will be continually inelectrical contact with one of the contacts 1l. These contacts are sospaced that for variations of a unit weight carried by the continuousconveyer one coil of the rheostat will either be cut in or out' ofcircuit, the unit weight being chosen depending upon the material to becarried and may be either an ounce, a pound or other unit. While I haveshown a rheostat controlled by an arm 10, it is to bei understoodthatany form of current regulat- 2 over which the belt v the, other end,it

direct reading grocers v v varies in direct which position the arm`being driven at the ing device may be used which will control thecurrent passing therethrough in proportion to the weight of the masssustained by the scale platform.

In the diagrammatic view shown, a magneto 14 is connected to the drivingpulley 2 by means of a belt 13 but it is to be understood that in thethe instrument some form of chain or gear drive would be used to avoidthe slip which necessarily occurs in a belt drive. nstead of the magneto14, any form of electric generator may be used in which the currentproportion to the speed. The armature coils of the magneto 14 or otherform of generator should be wound with-.a wire having a zero temperaturecoe .cient so that the strength of current generated thereby will not beaected by the temperature conditions under which the generator acts. Thearmature terminals of the magneto or generator 14 are connected by thewires- 15 and 16 to the ends of a Wheatstones bridge which consists oftwo branch circuits, one of which branches includes the resistances 17and 18, while in the other branch a resistance 19, the coils 11 of therheostat and its arm 10 are connected in series. Substituted for thegalvanometer usually employed in a Wheatstones bridge is an electricalmeter 20 which is bridged between the two branch circuits by means of aconductor 21. 1f it is desired to record the amount of material carriedby the conveyer for any 'given period of ltime which is the bestpractical construction, a recording integrating electrical meter isused.

The Wheatstones bridge is preferably balanced when the resistance' coils11 of the rheostat are entirely cut 10 is in its lower left-handposition and the pointer 6 of the scale stands at its Zero indicatingposition, the scale 6 being so calibrated that the pointer 6 indicateszero when there is4 no weight sustained bythe scale platform 5 exceptthe weight of the belt itself. The Wheatstones'bridge may also bebalanced when the resistance coils-11 of therheostat are entirely cutout of the circuit in which lcase it would be necessary to reverse theposition of the arm 10 and the pointer 6,

forml is desirable being hereinafter referred to. v

- The operation in general is as follows zssuming that the vcontinuousconveyer is desired speed but no material is carried'by it, theWheatstones bridge is therefore in balanced condition and the currentgenerated by the magneto or generator 14 passes through the balancedcircuits and will not affect the meter 20.

As the material is fed onto the belt conveyer'l, its weight, .will betransmitted to the platform `54 and move the pointer 6 and practicalconstruction of.

,taneous variations in the into the circuit, in'

the rheostat in a clockwise direction which will successively cut outthe resistance coils 11. The circuits of the bridge will thereforebecome unbalanced and a portion of the current generated by thegenerator 14 then passes through the electrical meter 20. The angularmovement of the arm 10 is directly proportional to the weight sustainedby the scale and since the current in any circuit varies in inverseprothe arm 10 of portion to the resistance of the circuit, the' currentwhichpasses through the meter 20 will vary in proportion to the weightof the material which the scale platform carries. Again, the magneto orgenerator is designed so that the current generated is directly pro- Asinstantaneous variations in the weight transmitted to the scale platform5 will affect the current passing through the meter 20, it isunnecessary that the portion ofthe belt conveyer directly above thescale platform 5 be disconnected from the other portions of the beltconveyer, it being only essentialthat the weight of the materialvcarried by the belt conveyer will be entirely transmitted to the scaleplatform 5 while in transit.

speed of the conveyer will also affect. the current passing through themeter 20 to cause the operation of the meter in the same manner as ifthe material carried by thebelt conveyerwere regarded as passing over agiven. point in a given instant of time.

Where the instrument is utilized as an automatic weighing device ytorecord the weight of the ous .conveyer during a usedf andin the form ofthe instrument shown'the meter used would comprise an' This is due tothe fact that instan- I ampere hour meter of the usual design.

Where such a meter is used it is necessary that the strength of currentthe same be increased or decreasedfor corresponding increases orv numberof 'units df weight conveyer, so that the speed of the movable member ofthe ampere hourmeter'will vary ratio which the proportionately V to thepassing through A .120 decreases in the" carried by the belt weight ofmaterial transmitted to the scale platform 5 bears to the standardweight" which the-instrument is-designedto carry..4

Because the current in 2l will not varyas y the effective resistanceofthe series of coils one coil will cause the same increase` or decreasein'the current in 21 irrespective of the position of the particular coilrelative to the other coils of the series. l

In calculating these resistances, there must be taken into considerationthe resistance of the circuits ofthe instrument, the resistancefof themagneto or-other form of generator,l andthe ratio which the weight atwhich'the particular coil will be cut out of circuit bears to thestandard weight for which the instrument is designed.

Referrin now to the modification disclosed in Fig. 2 of the drawings,the circuit connections are similar to those shown in Fig. 1, but theresistance coils 21 which form gvpart ofone of the balanced circuits ofthe heatstones bridge, are adapted to be cut in or out of circuitby'means of a dynamometer which measures the energy requiredl to drivela-'shaft 24. known form of dynamometer may be used and in the drawing,a N'eers rotary transmitting dynmometer is shown. This dynamometer iscon-` nected between the driven shaft 24 'and a driving shaft 25, andcomprises disks 26 and 27 whlch` are keyed to the shafts 24' and 25,respectively. Chains 28 anchored to the disk 26 pass over pulleyscarriedl by the disk 27 -`afd are connected to a -spider 29 which iskeyed to but slidably mounted on the shaft25. The pull of the-chains 28is `resisteddc'y, the tension of the springs 30 which tension isrecorded on a dial 31 by means df an annularly moving ointer 32.

`Mounted on the shaft of the pointer 32 is j an arm 33 which, similar tothe form disclosed in Fig. 1, is adapted to cut out the resistance21which forms a part of the circuit in the Wheatstones brid e. Thegenerator 14 is driven either from s aft 24 or 25.

When the driving shaft 25 transmits its power t the driven shaft 24, thedynamometer will move the indicating pointer 32 in direct proportion tothe energy required to vrotatethe driven shaft and the arm- 33 lwhen theshafts are, runnin light or at rest is preferably so arranged t at allof the resistance coils 21 are out into circuit. Under load, the arm 33will -be rotated in a clockwise direction .to cut out sections of therheostat 21 in direct proportion to the power required to drive thedriven shaft. 'Since the magneto 14 is connected to the driving shaft.24, lthe strength of current passing through the Wheatstones bridgewill therefore be' in direct proportion to thehspeed. Assuming that ameter is bridged between the 'balanced circuits of the Wheatstonesbridge, since the strength of current which 'affects this ammeter isdirectly proportional movable body rather lmeter of the ordinarystantaneous readings tions or movements of themeter will be dii rectlyproportional to the Yproduct 0f these factors. The work done in driving.the shafts multiplied by the speed with which the force acts, i, e.,rate of doing work, will give the power required to drive the shafty andthe instrument may be calibrated to read in horse-power orl in any otherunit. If it is not desired that the angular deflection of the ammetersneedle be in direct proportion to power required to drive the shaft, thecoils 21 may be made of equal resistance, in which case the needledeflections produced by predetermined powers must be marked on the scaleof the ammeter and the instrument thus calibrated.`

If it is desired' to determine the horsepowerhours or the amount ofpower consumed in driving the shaft forl any predetermined period oftime, the meter 20 may be replaced by an integrating hour meter whichwill record these instantaneous values and thus give the sum or total ata single reading.

lWhere the instrument is used to indicate the horsepower and for variousother uses, it is frequently desirable that the instrument indicate theinstantaneous values of the product of the mass, force and speed of thethan the sum or total of the instantaneous values of these products.

In this instance, a direct reading electrical type may be used. lf anammeter is used, it is obvious that with each additional unit definingthe prod= uct of the mass and force, there should be a correspondingincrease in the strength of the current that passes through the ammeter.

The Wheatstones bridge is, therefore, balanced with the resistance coils11 or 21 entirely out in circuit as in the form' disclosed, which coilsmay be if desired. `The ammeter may be calibrated as the variations inthe strength of current produced by cutting in or out successiveresistance coils 11 or 21 will produce determined deliections of themovable needle of the ammeter, the respective positions of which may bemarked on the dial so as to be read in the desired units.

The instrument may also that a voltmeterrrnay be used reading bedesigned as the direct yadditional unit corresponding to the product ofthe mass and force of the body there should be a corresponding increasein the voltage of the current passing through the voltmeter which willlgive inof the increase 'in the units of the product of the mass andforce.

of equal resistancey instrument and here it is necessary i that for eachThe Wheatstones bridge would, in this instance, be balanced when theresistance coils 11 or 21 are cut out of circuit so that asythe coils-11 or 21 are successively cut in by the angular advance of the arm orits equivalent which will be in a reverse position to that shown as hasbeen referred to. When tion or movement of the needle ofthe volt-vmeter, the respective positions of which may be marked on the dial sothat the instrument will give a direct reading in the ref quired units.If a recording integrating instrument is used, the resistance coils 11or 211 should be of varying resistance which maybe calculated in themanner heretofore described. 4

It will therefore be seen that the instrument has ja peculiar adaptationwhere it is desired to determine the Work done or consumed-in' driving amoving body and the invention may b e applied in numerous ways to movingbodies other than on rotating shafts.

It will also be seen that the instrument has special adaptationswhere itis desired to place one or more direct reading instruments- 1n the samecircuit which may be located at different localities or at positionsremote from. the weigher or other -devices with which the instrument isconnected as, for example, the directreading instrument may be placedvinthel operating companys Y office at `any distance from the continuouslweigher to which it is connected.

conveyer and generatinga current in direct proportion to its own speed,and means controlled by said scale for varying the current in one ofsaid branches and unbalancing said branches whereby a current will flow'through said meter. Q

2. An automatic weighing device for continuous-conveyers comprising aWheatstones bridge, an electrical integrating meter connected betweenthe legs of said bridge, lmeans in one leg of the'bridge controlledbythe weight of the material carried by the con-` veyer at a given pointfor varying the current therein and a dynamo-electric machine drivenproportionately to the speed of the conveyer and generating a current indirect proportion to its `own speedfor supplying current to said bridge.

In witness whereof, li subscribe my signature, in the presence ofv twowitnesses.

Y BEMISS N. DAVIS. Witnesses: A.. C. DUoA'rEL, f

